Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sun, 20 Aug 2017 20:23:26 +0200 | From | Lukas Wunner <> | Subject | Re: [PATCH 1/2] PM: docs: Describe high-level PM strategies and sleep states |
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On Sun, Aug 20, 2017 at 06:05:05PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Reorganize the power management part of admin-guide by adding a > description of major power management strategies supported by the > kernel (system-wide and working-state power management) to it and > dividing the rest of the material into the system-wide PM and > working-state PM chapters. > > On top of that, add a description of system sleep states to the > system-wide PM chapter.
Found no typos and no factual inaccuracies, the only thing that irritated me a bit was the part about "working state" power management:
> +The other strategy, referred to as the > +:doc:`working-state power management <working-state>`, is based on adjusting the > +power states of individual hardware components of the system, as needed, in the > +working state. In consequence, if this strategy is in use, the working state > +of the system usually does not correspond to any particular physical > +configuration of it, but can be treated as a metastate covering a range of > +different power states of the system in which the individual components of it > +can be either ``active`` (in use) or ``inactive`` (idle). If they are active, > +they have to be in power states allowing them to process data and to be accessed > +by software. In turn, if they are inactive, they are expected to be in > +low-power states in which they may not be accessible. > + > +If all of the system components are active, the system as a whole is regarded as > +``runtime active`` and that situation typically corresponds to the maximum power > +draw (or maximum energy usage) of it. If all of them are inactive, the system > +as a whole is regarded as ``runtime idle`` which may be very close to a sleep
The code uses the terms pm_runtime_active() and pm_runtime_suspended(), not "runtime idle". Taking the ->runtime_idle callback as guidance, "runtime idle" would mean that a component is runtime active, but idling and could thus be transitioned to runtime suspended state. However above it says that if it's idle, it's already "in low-power states and may not be accessible". For someone reading this it may be difficult to reconcile it with the terminology used in the code.
Otherwise, Reviewed-by: Lukas Wunner <lukas@wunner.de>
Thanks,
Lukas
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